Signals that operate at high frequencies or travel along long signal path lengths are often terminated to prevent degradation of the signal through ringing and other effects. The transmitted signal is optimally received when the receiving end of the signal path has an impedance matched to the impedance of the transmission point. There are certain situations, such as during testing or when the location of the termination is on another card, where it is desirable to tie the receiver input to a ground level to prevent the reception of spurious signals. A jumper may be used to provide a user with the opportunity to set the mode of operation of the receiver input, such as termination through impedance matching or grounding. With previous designs, the host device could not determine if it had control over the termination or if the jumper was forcing the terminators to be enabled/disabled. This is a problem if the software controlling the testing wants to warn or notify the end user that the termination is software controlled or if the user must examine the jumper settings.
Therefore, it would be desirable to provide a method and circuit to allow better control over signal bus line terminations.